C-h v problem on Emacs trunk on Mac OS X

C-h v problem on Emacs trunk on Mac OS X

[Ben Key]

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I am using Emacs 24.0.50.2 built from revision 103358 of the Emacs trunk on
Mac OS X.  When I do a C-h v <var-name> I sometimes get output that includes
the line "Not documented as a variable" where the variable documentation
ordinarily would be.  For example, C-h v cursor-type displays the following.

cursor-type's value is t

  Automatically becomes buffer-local when set in any fashion.

Documentation:
Not documented as a variable.

This is not the only variable that has this problem.  I get the same results
for emacs-basic-display and I have seen several others.  However, for some
variables, such as emacs-version, I do not see this problem.

In Emacs 23.2, I do not see this problem.

I started Emacs with the -Q command line argument to make certain that the
cause was not in my initialization files.

Does anyone have any ideas what might be causing this problem or should I
just start debugging Emacs to look for the cause?

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Re: C-h v problem on Emacs trunk on Mac OS X

[Ben Key]

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Hello,

I have begun looking into this problem.  So far I  have learned that the
documentation is generated by the make-docfile tool.  I have also learned
that the cursor-type variable is defined in buffer.c.  As a test I ran
make-docfile
against buffer.c and looked at the output.  The documentation of the
cursor-type variable was not included in the output.

I will begin looking into this problem with make-docfile tomorrow.

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Re: C-h v problem on Emacs trunk on Mac OS X

[Ben Key]

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Hello,

I have some more information on the cause of this bug.  It turns out that it
is an unintended consequence of the recent BVAR and KVAR changes.  The
parser used be make-docfile is very simplistic.  It assumes that when it
sees a DEFVAR_PER_BUFFER it can start looking for the documentation after 2
commas.  This assumption is no longer valid because of the added comma in
the usage of the BVAR macro.

The following patch appears to fix this problem.

<patch>
=== modified file 'lib-src/make-docfile.c'
--- lib-src/make-docfile.c    2011-02-09 00:30:33 +0000
+++ lib-src/make-docfile.c    2011-02-21 09:39:03 +0000
@@ -815,7 +815,7 @@
       if (defunflag)
     commas = 5;
       else if (defvarperbufferflag)
-    commas = 2;
+    commas = 3;
       else if (defvarflag)
     commas = 1;
       else  /* For DEFSIMPLE and DEFPRED */

</patch>

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Re: C-h v problem on Emacs trunk on Mac OS X

[Chong Yidong]

Ben Key <bkey76@gmail.com> writes:

> I have some more information on the cause of this bug.  It turns out
> that it is an unintended consequence of the recent BVAR and KVAR
> changes.  The parser used be make-docfile is very simplistic.  It
> assumes that when it sees a DEFVAR_PER_BUFFER it can start looking for
> the documentation after 2 commas.  This assumption is no longer valid
> because of the added comma in the usage of the BVAR macro.
>
> The following patch appears to fix this problem.

Thanks; committed.